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Home , Pinch (plasma physics), Sceptre (fusion reactor)

Tokamaks and pinches (history, taxonomy)

Gergő Pokol

BME NTI

Fusion devices 9. March 2020 Gergő Pokol: and pinches

1. Take your mobile phone or laptop

2. WiFi password: wigner2/wigner2008 – or mobilnet

3. Browser: Kahoot.it

4. Code on screen

5. Name: Neptun code !!!

6. Evaluation: – Good answer  +1 score – Winner of Kahoot  +1 score

At the end of semester: normalize with number of questions to get %. 2 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

Provisional program

Date Lecturer Topic

10. FebruaryPokol Theory review (fuel flow, magnetic confinement, transport, tokamak, ) Technology review (vacuum, , heating, current drive, plasma 17. FebruaryPokol diagnostics) 24. FebruaryVeres (history, Wendelstein line, stellarator taxonomy) 2. MarchPokol Wendelstein 7-X stellarator 9. MarchPokol Tokamaks and piches (history, tokamak taxonomy) 16. MarchPokol JET (goals, structure, status) 23. MarchPokol ITER (goals, structure, status) 30. MarchPokol DEMO, Fusion Roadmap 6. AprilPokol Mid-term exam 20. AprilPokol Middle-sized tokamak program 27. AprilPokol , spherical tokamaks, US fusion program 4. MayPokol Far East superconducting tokamaks 11. MayPokol Tokamak simulation exercise 18. MayPokol Final exam

3 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Pinch effect

Pinch effect discovered in 1904 in liquid metals: Radial compressing force in a conductor caused by current.

The magnetic field strength:

The force balance :

Sausage instability Kink instability

4 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Pinch devices - types

Toroidal Z-pinch: high current, high pressure plasma stabilized by a toroidal magnetic field. q-pinch: stable configuration, but problems with ends. Racetrack configuration unstable.

(, RFP)

High , but unstable configurations!

5 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Early pinch devices

- 1947 UK - Sir G.P. Thomson and P. C. Thonemann - toroidal geometry - ~ cm minor radius - glass vacuum chamber - kink instability

ZETA pinch (Sceptre)

- Zero Energy Toroidal Assembly -1954 – 1957 - UK - stabilized with toroidal magnetic field - detected – not ! - not continued

6 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Reversed Field Pinch (RFP)

http://www.igi.cnr.it/?q=system/files/rfx_en_0.mpg 7 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Reversed Field Pinch (RFP)

- RFX, Italy - reverse Bt on axis Quasi Single Helicity - dynamo - many modes - active stabilitazion - QSH ~ stellarator

8 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

I.E. Tamm, A.D. Sakharov

9 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

10 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

11 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

https://www.youtube.com/watch?v=-wJaFAtCKPc 12 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

tE

1 kT t D  B B 16 eB

British measurements prove Soviet tokamak results in

1969! 13 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Thomson scattering today

Thomson scattering: light scattering on free charged particles (in practice on electrons) Scattered intensity  plasma density Spectrum  Electron temperature (Doppler) (e-velocity: 107 m/s) Scattering cross-section is extremely small: possible only with pulsed laser: 1-10 J, few ns, 1 GW!!! - 10-20 Hz Local measurement from crossing of laser and observation.

14 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

15 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

16 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

17 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

18 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

To be re-opened as T-15MD ?

19 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

Limiter Divertor D-T operation Strong shaping Spherical

T 8 Superconducting

20 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

Limiter Divertor D-T operation Strong shaping Spherical

T 8 Superconducting

21 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches Sources

V.P. Smirnov: Tokamak foundation in USSR/Russia 1950–1990, , 50, 014003 (2010) http://www.igi.pd.cnr.it http://www.tokamak.info/

Robert Arnoux: Which was the first "tokamak" — or was it "tokomag"?, ITER NEWSLINE 55 (2008)

L. A, Artsirnovich: Research on Controlled Thermonuclear Reactions in the USSR, Atoms for Peace Geneva Conference (1958)

22 Fusion devices, 9. March 2020 Gergő Pokol: Tokamaks and pinches

1. Take your mobile phone or laptop

2. WiFi password: wigner2/wigner2008 – or mobilnet

3. Browser: Kahoot.it

4. Code on screen

5. Name: Neptun code !!!

6. Evaluation: – Good answer  +1 score – Winner of Kahoot  +1 score

At the end of semester: normalize with number of questions to get %. 23 Fusion devices, 9. March 2020